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UNO [17]
3 years ago
5

How do you factor `x^{2}-4x-21=0`

Mathematics
1 answer:
KengaRu [80]3 years ago
4 0

Answer:

<u>X=7,-3</u>

Step-by-step explanation:

x^(2)-4x-21=0

(x-7)(x+3)=0

x=7,x=-3

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What is the image of (6,-4) after a reflection over the y-axis?
kirill115 [55]

Answer:

(-6,-4)

Step-by-step explanation:

Hope this helps! (:

3 0
3 years ago
Help<br> -9x + 3.0 &gt; 6.6<br> Group of answer choices<br><br> x 0.4<br><br> x 2.4
Y_Kistochka [10]

Answer:

x  0.4

Step-by-step explanation:

Isolate the variable by dividing each side by factors that don't contain the variable.

3 0
3 years ago
Consider the universal set U and the sets X, Y, Z. U={1,2,3,4,5,6} X={1,4,5} Y={1,2} Z={2,3,5} What is (Z⋃X′)⋂Y?
beks73 [17]

X' = U - X

= {1,2,3,4,5,6} - {1,4,5}

= {2,3,6}

(ZUX') = {2,3,5} U {2,3,6}

= {2,3,5,6}

(Z⋃X′)⋂Y = {2,3,5,6} ⋂ {1,2}

= {2}

3 0
3 years ago
Jenny and Lester are running the 100 meter dash. Jenny completes it in 15.2 seconds and Lester completed it in 15.7 seconds. Wha
matrenka [14]

Jenny won the race as she finished the race much more quickly and has greater average speed than Lester.

\sf \boxed{\sf speed:\frac{distance}{time \ taken} }

Jenny: distance/time = 100/15.2 = 6.58 m/s = 6.6 m/s

Lester: distance/time = 100/15.7 = 6.37 m/s = 6.4 m/s

3 0
2 years ago
A card is being drawn from a standard deck of playing cards. Find each probability.
EastWind [94]
These are 6 questions and 6 answers.

To find each probability we will use the definition of probability:

Probability = number of positive outcomes / number of total possible outcomes

1) <span>P(Jack or ten)
</span>

<span>Answer: 2/13 ≈ 0.12
</span>

Justification:

i) Positive outcomes: A standard deck of cards has 4 jacks and 4 tens, then those are 4 + 4 = 8 different positive outcomes.

ii) Possible outcomes: a standard deck of cards has 52 different cards, so, that is a total of 52 different possible outcomes

 
iii) Probability, P


P = number of positive outcomes / number of total possible outcomes

P = 8 / 52 = 2/13 ≈ 0.15

<span> 2.P(red or black)
</span>

Answer: 1

Justification:

i) Positive outcomes

Half of the cards are red and half of the cards are black, so they both add for the total of the cards = 52


ii) Possible outcomes: 52 cards


iii) Probaility, P 

P = number of positive outcomes / number of total possible outcomes

P = 52 / 52 = 1

<span> 3.P(queen or club)
</span>

Answer: 4/13 ≈ 0.31

Justification:


i) Positive outcomes

There are 4 Queens.

There are 1/4 of 52 clubs = 1/4 × 52 = 13 clubs.

But you cannot add all of them, because one club is the Quenn of Clubs.

Then, the total number of different Queens and clubs is 4 + 13 - 1 = 16



ii) Possible outcomes: 52 different cards


iii) Probaility, P

P = number of positive outcomes / number of total possible outcomes

P = 16 /52 = 4 / 13 ≈ 0.31


<span> 4.P(red or ace)
</span>

Answer: 7 / 13 ≈ 0.54


Justification:


i) Positive outcomes

Half of the cards are red: 26

There are 4 aces. 

Since 2 aces are red, the number of different red and aces cards is: 26 + 4 - 2 = 28

ii) Possible outcomes: 52 different outcomes


iii) Probaility, P

P = number of positive outcomes / number of total possible outcomes

P = 28 / 52 = 7 / 13 ≈ 0.54

<span> 5.P(diamond or black)
</span><span>
</span>
Answer: 1/2 = 0.5

Justification:

i) Positive outcomes

There are 52 / 4 = 13 diamonds

There are 26 black cards.


All the diamonds are black cards.

Then, the number of different diamond or black cards is 13 + 26 - 13 = 26

ii) Possible outcomes: 52 different cards.

iii) Probaility, P

P = number of positive outcomes / number of total possible outcomes

P = 26 / 52 = 1/2 = 0.5

6.P(face card or spade)

Answer: 11/26 ≈ 0.42


Justification:

i) Positive outcomes

Face cards are jacks, queens and kings. That is 3 × 4 = 12 different cards.

The spades are 13 cards.

Since, 3 of the faces are spade cards, the number of different cards of those types are 12 + 13 - 3 = 22


ii) Possible outcomes: 52 different cards


iii) Probaility, P

P = number of positive outcomes / number of total possible outcomes

P = 22 / 52 = 11 / 26 ≈ 0.42
4 0
3 years ago
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